134 U.S. 418, argued 13, 14 Jan. 1890, decided 24 Mar. 1890 by vote of 6 to 3; Blatchford for the Court, Miller concurring, Bradley, Gray, and Lamar in dissent. When the Court in Munn v. Illinois (1877) upheld legislative power to control railroad rates, it also ruled that governmentally set rates were not subject to judicial review. This ruling was an application of the traditional principle that the Court determined the Constitution's allocation of power among branches of government but did not supervise the discretionary exercise of those powers. Yet in Chicago, M. & St. P. Ry. v. Minnesota, the Court voided legislation that did not permit judicial review of rates set by the state's Railroad and Warehouse Commission. This was the first case in which the Court adopted a modern approach to the constitutional arrangements of the regulatory state. Implicit in the Court's ambiguous opinion was the fundamental tenet of contemporary administrative law: due process requires judicial review of administrative agency procedures and decisions to determine their fidelity to constitutional norms. In particular, the Court asserted the power to judge the reasonableness of utility rates. With this decision, the Court began to review not only whether a particular branch of government had authority to act but also the reasonableness of the procedures through which officials act and the reasonableness of the decisions themselves.
Stephen A. Siegel